Share-Based Compensation (Narrative) (Details) (USD $)	11 Months Ended	12 Months Ended
	Nov. 27, 2011	Dec. 31, 2011
Acquisition cost per share		$ 30.00
Total share-based compensation, net of tax	$ 6,600,000
Share-based compensation included in Operation and maintenance expense	10,100,000
Shares issued under equity and performance incentive plan (EPIP)	4,500,000
Share-based Compensation Arrangement by Share-based Payment Award Accelerated Compensation Cost	5,500,000
Share-based Compensation Arrangement by Share-based Payment Award Accelerated Compensation CostNetofTax	3,600,000
DP&L [Member]
Total share-based compensation, net of tax	6,600,000
Share-based compensation included in Operation and maintenance expense	10,100,000
Shares issued under equity and performance incentive plan (EPIP)	4,500,000
Share-based Compensation Arrangement by Share-based Payment Award Accelerated Compensation Cost	5,500,000
Share-based Compensation Arrangement by Share-based Payment Award Accelerated Compensation CostNetofTax	3,600,000
Restricted Shares [Member]
Acquisition cost per share	$ 30.00
Share-based compensation included in Operation and maintenance expense	5,300,000
Restricted Shares [Member] | DP&L [Member]
Acquisition cost per share	$ 30.00
Share-based compensation included in Operation and maintenance expense	5,300,000
Director RSU's [Member]
Acquisition cost per share	$ 30.00
Share-based compensation included in Operation and maintenance expense	600,000
Director RSU's [Member] | DP&L [Member]
Acquisition cost per share	$ 30.00
Share-based compensation included in Operation and maintenance expense	600,000
Management Performance Shares [Member]
Acquisition cost per share	$ 30.00
Share-based compensation included in Operation and maintenance expense	1,800,000
Management Performance Shares [Member] | DP&L [Member]
Acquisition cost per share	$ 30.00
Share-based compensation included in Operation and maintenance expense	1,800,000
Performance Shares [Member]
Acquisition cost per share	$ 30.00
Share-based compensation included in Operation and maintenance expense	2,400,000
Performance Shares [Member] | DP&L [Member]
Acquisition cost per share	$ 30.00
Share-based compensation included in Operation and maintenance expense	$ 2,400,000